Plant growth regulant method

ABSTRACT

The disclosure relates to a method for employing di(hydrocarbyl)carbamoylphosphonates to regulate the growth rate of plants.

Uni

Bucha et a1.

11 etet [1 1 PLANT GROWTH REGULANT METHOD [75] Inventors: Harry C. Bucha; William P.

Langsdori, J12, both of Wilmington, Del.

[73] Assignee: E. l. du Pont de Nemours and Company, Wilmington, Del.

[22] Filed: May 18, 1972 [21] App]. No.: 254,670

Related U.S. Application Data [63] Continuation of Ser. No. 850,220, Aug. 14, 1969,

abandoned.

[52] U.S. Cl. 71/76, 71/86 [51] Int. (Ii. A0ln Nov. 19, 1974 Primary Examiner-James 0. Thomas, Jr.

[57] ABSTRACT The disclosure relates to a method for employing di(hydrocarbyl)carbamoylphosphonates to regulate the growth rate of plants.

10 Uaims, N0 Drawings PLANT GROWTH REGULANT METHOD This is a continuation of application Ser. No. 850,220, filed Aug. 14, 1969 now abandoned.

BACKGROUND OF THE INVENTION This invention relates to the discovery that di(hydrocarbyl)carbamoylphosphonates are useful for retarding the growth rate of plants. The compounds of this'invention are especially useful for controlling the growth of woody vegetation.

Some of the compounds of this invention are known to the art as herbicides as is evidenced by US. Pat. No. 3,005,010.

It has now been discovered that the application of a controlled amount of the compound of this invention to woody vegetation results in a decrease in the rate of plant growth with little or no apparent damage to the treated plant.

SUMMARY OF THE INVENTION where R is selected from the group consisting of alkyl of one through eight carbon atoms, chloroalkyl of two through eight carbon atoms containing up to three chlorine atoms, bromoalkyl of two through eight carbon atoms containing up to three bromine atoms, alkoxyalkyl of three through ten carbon atoms, total, alkenyl of two through eight carbon atoms, alkynyl of three through four carbon atoms, phenyl or benzyl;

R is selected from the group consisting of alkyl of one through eight carbon atoms, chloroalkyl of two through eight carbon atoms containing up to three chlorine atoms, bromoalkyl of two through eight carbon atoms containing up to three bromine atoms, alkoxyalkyl of three through ten carbon atoms, total, alkenyl of two through eight carbon atoms, alkynyl of three through four carbon atoms, phenyl, or benzyl;

R is selected from the group consisting of hydrogen,

alkyl of one through four carbon atoms, hydroxyalkyl of two through four carbon atoms, alkenyl of three through four carbon atoms or alkynyl of three through four carbon atoms;

R is selected from the group consisting of hydrogen,

alkyl of one through four carbon atoms, hydroxyalkyl of two through four carbon atoms, alkenyl of three through four carbon atoms or alkynyl of three through four carbon atoms;

R and R can be taken together to form a bridge consisting of (CH O(CH or (CI-I where n is 4, 5 or 6; and one of R or R can be 1 where R is hydrogen or alkyl of one through four carbon atoms and R is hydrogen or alkyl of one through four carbon atoms.

DESCRIPTION OF THE INVENTION This invention is founded on the discovery that the compounds of Formula (1) can be applied to woody vegetation to retard the growth rate of said vegetation.

Within the compounds of Formula (1) those compounds wherein R and R are the same are preferred for economic reasons. Further, those compounds of Formula (1) were R and R are each hydrogen and R and R are each selected from the group consisting of alkyl of one through four carbon atoms or alkenyl of two through four carbon atoms are most preferred for their particularly high plant growth retardant activity.

The di(hydrocarbyl)carbamoylphosphonates which are useful in the method of this invention can be prepared by a variety of methods available in the literature. The method employed by Nylen, Chem. Ber. 57, 1023 (1924), and Reetz, et al., J.A.C.S. 77, 3813-3816 (1955) can be generally applied to the preparation of the compounds of Formula (1 The method comprises treating an appropriate trialkyl phosphite with a chloroformate or thiolchloroformate and then treating the resulting dialkyl alkoxycarbonylphosphate or a1kylthiolcarbonylphosphate with ammonia or an appropriate amine to give the desired carbamoylphosphate. These reactions can be represented as follows:

In the above equation R, R and R are defined as above, R is lower alkyl, preferably methyl or ethyl and X is oxygen or sulfur. In most instances X will preferably be oxygen, however, when the amine in Equation (3) has relatively low resistivity X is preferably sulfur. For more information relating to the reaction when X is sulfur, reference can be made to US. Pat. No. 3,005,010.

The starting materials of Equation (2), above, are commercially available or can be readily prepared using methods. known to the art. The reaction between the dialkylalkoxycarbonylphosphonate and the amine or ammonia described above is generally run at a temperature of from 20C. to C. A solvent is not necessary, but if a solvent is used, one which is inert to the reactants employed should be chosen. Suitable solvents include ethers, hydrocarbons or chlorinated hydrocarbons.

Illustrative of the phosphite esters which can be employed in the reaction are esters such as trimethyl phosphite, triethyl phosphite, trialkyl phosphite, tris-(2- chloroethyl) phosphite and trioctyl phosphite.

Mixed phosphites can, of course, also be used, in which case mixed ester products can be obtained. Illustrative mixed phosphite esters include dioctyl methyl phosphite, diphenyl ethyl phosphite and dibenzyl methyl phosphite.

Illustrative of the acid chlorides employed in the above reaction are methyl chloroformate, ethyl chloroformate, methyl thiolchloroformate and ethyl thiolchloroformate.

Illustrative of the carbonylphosphonate intermediates which can be used as a starting material in the reaction of Equation (3) to prepare the compounds of Formula (1) are dimethyl methoxycarbonylphosphonate, dimethallyl methoxy carbonylphosphonate, dibutyl ethoxycarbonylphosphonate, diphenyl propoxycarbonylphosphonate, benzyl ethyl ethoxycarbonylphosphonate, bis( 2-chloroethyl )methylthiolcarbonylphosphonate and diethyl ethoxycarbonylphosphate.

The carbonylphosphonate ester intermediates generally are liquid products. Usually it is not necessary to purify them further after removal of the by-product alkyl halide and solvent. However, if desired, purification can be effected by distillation under reduced pressure. Purification and separation of the desired intermediate may be desirable where a mixed carbonylphosphonate is prepared. It will be understood that the term mixed carbonylphosphonate is used to identify those compounds which contain more than one ester group such as benzyl ethyl ethoxycarbonylphosphonate.

In the procedure outlined in Equation (3), the dialkyl alkoxycarbonylphosphonates can be reacted with ammonia or an amine with or without a solvent present. It is desirable that a solvent be employed where considerable heat of reaction is involved in the mixing of reactants. Generally, however, mixing can be effected without solvent present and external heating may be re quired to complete the reaction.

Illustrative of the amines whch can be employed in the reaction of Equation (3) are methylamine, allylamine, butylamine, dibutylamine, morpholine and piperidine.

An alternative method for the synthesis of those compounds of Formula l where R and/or R is dichloroalkyl or dibromoalkyl can be employed. The method comprises preparing the corresponding alkenyl carbonylphosphonate and then adding a halogen across the double bond to give the desired product.

The compounds of Formula l generally are liquids, but many are solids. The products are generally acceptable for use as plant growth retardants after removal of the byproduct alcohol and solvent, when employed. However, if desired, the liquid products can be purified by distillation.

Those compounds of Formula (1) with short-chain substituents have good solubility in water, lower alcohols and ketones. Higher homologs show decreased solubility in water, but have increased solubility in most organic solvents. The differences in physical properties can be employed to advantage in the preparation of various types of agricultural formulations as will be illustrated.

The preparation of the compounds of Formula (1) is further illustrated in the following Examples. Parts and percentages in the Examples are by weight unless otherwise specified.

Example 1 One hundred and thirty parts of trimethyl phosphite are heated to C. and treated with 100 parts of methyl chloroforrnate at a rate sufficient to maintain a reaction temperature of at least 100C. After gas evolution stops, the residue is distilled to obtain 131 parts of dimethyl methoxycarbonylphosphonate, b.p. 8385C./l.2 mm., N 1.4210.

Twenty parts of the above liquid are heated to 40C. and 2.2 parts of anhydrous ammonia are added over a 2-hour period. The solidified reaction mass is essentially pure dimethyl carbamoylphosphonate. m.p. C.

Examples 2 8 The procedure of Example 1 is repeated by substituting an equivalent amount of the indicated Alkoxycarbonylphosphonate Ester and Amine to produce the Carbamoyl Product. These products are soluble in water, as well as in lower alcohols and ketones.

Alkoxycarbonyl- Ex. phosphonate Ester Amine Carbamoyl Product 2 diethyl ammonia diethyl ethoxycarbonylphos carbamoylphosphonate phonate 3 diethyl methylamine diethyl methoxycarbonylmethylcarbamoylphosphosphonate phonate 4 diethyl ethylamine diethyl methoxycarbonylethylcarbamoylphosphosphonate phonate 5 diethyl dimethylamdiethyl ethoxycarbonylphosine dimethylcarbamoylphosphonate phonate 6 dipropyl ammonia dipropyl methoxycarbonylcarbamoylphosphonate phosphonate 7 dimethyl dimethyl methoxycarbonylpropylcarbamoylphosphosphonate phonate pylamine(stoichiometric amounts) 8 dimethyl ethanolamine dimethyl methoxycarbonyl- (stoichiomeb Z-hydroxyethylcarphosphonate ric amounts) bamoylphosphonate Example 9 A slight excess (5l0%) of gaseous ammonia is introduced into a stirring mixture of 11 parts of diallyl methoxycarbonylphosphonate (from triallyl phosphite and methyl chloroforrnate) and 200 parts of tetrahydrofuran. The temperature increases from 25C. to 28C. spontaneously. The mixture is then heated to 35C. and maintained at this temperature for 2 hours. The slightly hazy solutionis filtered, and solvent is removed from the filtrate at 50C. under reduced pressure (15 mm.). The residual solid is recrystallizedfrom benzene, giving 6 parts of white crystalline diallyl carbamoylphosphonate, m.p. 9 l94C.

Examples 10-24 The procedure of Example 9 is repeated substituting equivalent amounts of the indicated Alkoxycarbonylphosphonate Ester and Amine to produce the Carbam oyl Product. These products, which may be liquids or solids, have very limited solubility in water, but are soluble in alcohols, ketones and aromatic hydrocarbons.

Alkoxycarbonyl Ex. phosphonate Ester Amine Carbamoyl Product dimethylallyl ammonia dimethylallyl methoxycarbonylcarbamoylphosphonate phosphonate ll dipropyl propylamine dipropyl propoxycarbonyl propylcarbarnoylphosphosphonate phonate l2 dibutyl dipropylamine dibutyl ethoxycarbonylphosdipropylcarbamoylphosphonate phonate l3 diamyl morpholine diamyl methoxycarbonyh morpholinocarbonylphosphonate phosphonate l4 dipropargyl piperidine dipropargyl methoxycarbonylpiperidincarbonylphosphosphonate phonate l5 di-sec-butyl diallylamine di-sec-butyl methoxycarbonyldiallylcarbamoylphosphosphonate phonate l6 diamyl butylethyladiamyl-N-butyl-N-ethyl ethoxycarbonylphosmine carbamoylphosphonate phonate l7 diallyl propargyladiallyl ethoxycarbonylphos' mine propargylcarbamoylphonate phosphonate l8 dibenzyl diethanoldibenzyl methoxycarbonylamine bis(2-hydroxyethyl) phosphonate carbamoylphosphonate l9 bis(2-octyloxyethyl)- ammonia bis(2-octyloxyethyl)carethoxycarbonylphosbamoylphosphonate phonate bis(l-butyl-3- ammonia bis(l-butyl-3- butenyl) butenyUcarbamoylphos methoxycarbonylphonate phosphonate 21 bis(3- ammonia bis(3-butynl)-carbutyl)methoxycarbamoylphosphonate bonylphosphonate 22 dimethyl 4-amino-ldimethyl methoxycarbonylbutanol 4-hydroxybutylcarphosphonate bamoylphosphonate 23 dimethyl metballyl dimethyl methoxycarbonylamine methallylcarbamoylphosphonate phosphonate 24 dimethyl l-methyldimethyl methoxycarbonylpropargyla- I-methylpropargylcarphosphonate mine bamoylphosphonate Example 25 To a mixture of 20.5 parts of diallyl carbamoylphosphonate and 100 parts of ethanol are added dropwise 16.0 parts of bromine. Isolation of the precipitated solid from the reaction mixture by filtration gives parts of bis(2,3-dibromopropyl)carbamoylpbosphonate. Additional product may be recovered by evaporation of the filtrate.

Examples 26 28 The procedure of Example 25 is repeated substituting an equivalent amount of the indicated Alkenyl Reagent for the diallyl carbamoylphosphonate and an equivalent amount of the indicated Halogen. for the bromine to obtain the indicated Product. Products in this category generally are water-insoluble, fat-soluble solids.

Twenty-seven parts of tris(2-chloroethyl) phosphite is stirred while 11.5 parts methyl thiolchloroformate are added slowly. The spontaneous reaction is controlled by external cooling, keeping the temperature during the addition at about 35C. When the reaction subsides, the mixture is heated to C. and maintained there for one-half hour. Stripping of the mixture under reduced pressure (15 mm; of mercury) at 50C. gives 27.5 parts of a crude residue of product, bis( 2- chloroethyl) methylthiolcarbonylphosphonate, suitable for use in the following reaction.

Eight and one-half parts of the above compound is mixed with 30 parts of tetrahydrofuran and treated with 5.5 parts of liquid ammonia. The reaction flash is fitted with a Dry-Ice-packed reflux condenser, and the mixture is heated up over a period of an hour to 54C. and held at that temperature for one-half hour. The reaction mixture is stripped leaving a solid residue as a product. Two recrystallizations from benzene give 2.4 parts bis(2-chloroethyl)carbamoylphosphonate, mp. 104106C.

Examples 30 37 The procedure of Example 29 is repeated substituting the indicated Alkylthiolcarbonylphosphonate Ester for the methyl bis(2-chloroethyl) methylthiolcarbonylphosphonate of the example and an equivalent amount of the indicated Amine for the ammonia to obtain the indicated Product.

-Continued Alkylthiolcarbonyl- Ex. phosphonate Ester Amine Product 33 methyl(l-propyl-lammonia methyl(l-propyl-ltritrichloromethylbuchloromethylbutyl) tyl) carbamoylphosphonate methylthiolcarbonylphosphonate 34 methyl(l-propyl-lammonia methyl(l-propyl-ltribromomethylbutribomomethylbutyl) tyl) carbamoylphosphonate methylthiolcarbonylphosphonate 3S dimethyl butylhydra' dimethyl methylthiolcarbonylzine Z-butylcarbazoylphosphosphonate phonate 36 dimethyl hydrazine dimethyl methylthiolcarbonylcarbazoylphosphonate phosphonate 37 bis(2- ammonia bis(2-bromoethyl) bromoethyl)methyltcarbamoylphosphonate hiolcarbonylphosphonate Example 38 A mixture of 28 parts diamyl methoxycarbonylphosphonate and 12.9 parts of dibutylamine is heated and stirred at 45 for 6 hours. The mixture is stripped under reduced pressure at 50 to remove by-product methanol, leaving a viscous liquid residue of 36 parts diamyl dibutylcarbamoylphosphonate. The product is suitable for use without purification.

Examples 39 44 The procedure of Example 36 is used without significant modification for reaction in the indicated Alkoxycarbonylphosphonate Ester with the indicated Amine to give the indicated Product. These products generally are viscous liquids or low-melting solids, soluble in aromatic hydrocarbons, alcohols and ketones.

Application and Formulation As stated earlier, this invention is founded on the discovery that the compounds of Formula (1) are useful for modifying the growth rate of plants. More particularly the compounds of this invention are useful as plant growth retardants. They also affect the flowering and fruit set of numerous plants.

The term plant growth retardant as used in this disclosure is to be understood to mean an agent which when applied to a plant or its environs will slow the growth of the plant without killing or causing extensive injury to said plant. This also includes a delaying response on bud sprouting or prolonging of the dormancy period.

The compounds of this invention can be used to retard the growth of woody vegetation such as trees, brush and shrubs. The compounds of this invention can also be used to control the growth of turf and other herbaceous vegetations.

The compounds of this invention can be applied as foliar sprays or as soil applications to retard the growth rate of such plants or to affect flowering and fruit set.

Preferably, the compounds of this invention are applied as a foliar spray to the point of runoff although lower-volume application may also be effective.

It is preferred that the application be made a short time prior to the period when maximum plant growth is anticipated, but application can also be made during the dormant stage or just after the plants have been trimmed. Or if flowering and fruit set are to be modifled, the treatment is applied before, during, or shortly after flowering.

It will be recognized that the rate of application is dependent upon the species to be treated and the results desired. In general, rates of from 0.25 to 20 kilograms per hectare are used although higher or lower rates can achieve the desired effect in some instances.

Plant growth regulant compositions of the present invention containing at least one of the compounds of Formula (1) above can be prepared by admixing at least one of these compounds with pest control adjuvants or modifiers to provide compositions in the form of dusts, solutions, water-dispersible powders, aqueous dispersions and emulsions.

Thus, the compounds of Formula (1) can be used with a carrier or diluent agent such as a finely divided solid, a solvent liquid of organic origin, water, a wetting agent, a dispersing agent, an emulsifying agent, or any suitable combination of these.

Compositions of the invention, especially liquids and wettable powders, contain as a conditioning agent one or more surface-active agents in amounts sufficient to render a given composition containing the compounds of Formula l readily dispersible in water or in oil. By the term surface-active agent, it is understood that wetting agents, dispersing agents, suspending agents and emulsifying agents are included. Suitable surfaceactive agents are set out, for example, in Detergents and Emulsifiers Annua (1968) by John W. McCutcheon, Inc. In general, less than 10 percent by weight of the surface-active agent is present in the compositions of this invention, although usually the amount of surface-active agent in these compositions is less than 5 percent by weight.

Among the formulations which are preferred are certain powders, water-soluble powders, certain dusts, certain emulsifiable oils, and solutions in certain solvents. In general, these preferred compositions will all usually contain a wetting agent, a dispersant, or an emulsifying agent.

Wettable powders are water-dispersible compositions containing the active material, an inert solid extender, and one or more surfactants to provide rapid wetting and prevent heavy flocculation when suspended in water.

The insert extenders which should be used in the preferred wettable powders of this invention containing the compounds of Formula (1) are preferably of mineral origin and the surfactants are preferably anionic or non-ionic.

The classes of extenders most suitable for the wettable powder formulations of this invention are the natural clays, diatomaceous earth, and synthetic mineral tillers derived from silica and silicate. Among non-ionic and anionic surfactants, those most suitable for the preparation of the dry, wettable products of this invention are solid forms of compounds known to the art as wetters and dispersants. Occasionally a liquid, nonionic compound classified primarily as an emulsifier may serve as both wetter and dispersant, but such types are usually avoided becuase of the difficulty in obtaining homogeneous distribution through the solid mass.

Most preferred fillers for this invention are kaolinites, montmorillonoids and attapulgite clay. Preferred wetting agents are alkyl benzene and alkyl naphthalene sulfonates, sulfated fatty alcohols, amines or acid amides, long chain acid esters of sodium isethionate, esters of sodium sulfosuccinate, sulfated or sulfonated fatty acid esters, petroleum sulfonates, sulfonated vegetable oils and ditertiary acetylinic glycols. Preferred dispersants are methyl cellulose, polyvinyl alcohol, sodium lignin sulfonates, polymeric alkyl naphthalene sulfonates, sodium naphthalene sulfonate, polymethylene bisnaphthalenesulfonate and sodium-N-methyl-N- (long chain acid) taurates.

Wetting and dispersing agents in these preferred wettable powder compositions of this invention are usually present at concentrations of from about 0.5 weight percent to 5 weight percent. The inert extender then completes the formulation. In some compositions small amounts of corrosion inhibitors and antifoarn agents might be added at the expense of the inert extender.

Those compounds of the invention which are water soluble can be dissolved in water without any other additive present and the resultant aqueous solution can be sprayed on the locus to be treated. However, in order to speed the solution rate, conditioners can be used such as wetting and dispersing agents as described above. Grinding can be employed to reduce the particle size and increase the surface area. Finally divided inert solid extenders can be blended into the formulation also. Upon extension with water the active component first disperses and then dissolves, leaving the inert solid in suspension.

Dusts are dense powder compositions which are intended for application in dry form, in accordance with the preferred compositions and methods of the invention. Dusts are characterized by their free-flowing and rapid settling properties so that they are not readily wind-borne to areas where their presence is not desired. They contain primarily an active material and a dense, free-flowing, solid extender.

Their performance is sometimes aided by the inclusion ofa wetting agent, and convenience in manufacture frequently demands the inclusion of an inert, absorptive grinding aid. For the compounds of this invention, the intert extender may be either of vegetable or mineral origin, the wetting agent is preferably anionic or non-ionic, and suitable absorptive grinding aids are of mineral origin.

Preferred inert solid extenders for the dusts of this invention are micaceous tales, pyrophyllite, dense kaolin clays, ground calcium phosphate rock such as that known as Phosphodust (a trademark of the American Agricultural Chemical Company), pulverized calcium carbonate, particularly the surface modified CCC diluent, and tobacco dust.

Preferred grinding aids are attapulgite clay, diatomaceous silica, synthetic fine silica and synthetic calcium and magnesium silicates. Preferred wetting agents are those previously listed under wettable powder formulations.

The inert solid extenders in the dusts of this invention are usually present in concentrations of from about 30 to weight percent of the total composition. The grinding aid will usually constitute 5 to 50 weight percent of the composition, .and the wetting agent will constitute from about 0 to 1.0 weight percent of the composition. Dust compositions can also contain other surfactants such as dispersing agents in concentrations of up to about 0.5 weight percent.

The wettable powders described above may also be used in the preparation of dusts. While such wettable powders could be used directly in dust form, it is more advantageous to dilute them by blending with the dense dust diluent. In this manner, dispersing agents, corrosion inhibitors, and anti-foam agents may also be found as components of a dust.

Emulsifiable oils are usually solutions of active material in solvents not miscible with water together with surfactants.

For the compounds of this invention, emulsifiable oils can be made by mixing the active ingredient with a solvent and surfactant or surfactants. Suitable sol vents for the compounds of this invention are hydrocarbons (substituted or unsubstituted), and water immiscible ethers, esters, or ketones. Suitable surfactants are those anionic or nonionic agents known to the art as emulsifying agents. Such compounds can be foimd listed by J. W. McCutcheon in Detergents and Emulsitiers Annual (1968).

Emulsifying agents most suitable for the compositions of this invention are, singly or in combinations, alkyl aryl polyethoxy alcohols, alkyl and alkyl aryl polyether alcohols, polyoxyethylene sorbitol or sorbitan fatty acids esters, polyethylene glycol fatty esters, fatty alkylol amide condensates, amine salts of fatty alcohol sulfates plus long chain alcohols and oil soluble petroleum sulfonates, alkylphenoxy, polyethoxy phosphates and alkyloxy polyethoxy phosphate esters. Such emulsifying agents will usually comprise fromabout 3 to 10 weight percentof the total composition.

Thus, emulsifiable oil compositions of the presentinvention will consist of from about 20 to 50 weight percent active material, about 40 to 7'5 weightpercent solvent, and about 3 to 10 weight percent emulsifier, as these terms are defined and used above.

While conventional applications of sprayable formulations have usually been made in a dilute form (for example, at a rate of about 200 liters per hectare or more), the compounds of this invention can also be applied at higher concentrations in the typical Ultralow-volume (ULV) or low-volume applications from aircraft or ground sprayers. For this purpose wettable powders can be dispersed in small amounts of aqueous or non-aqueous carrier. Emulsifiable concentrates can be used directly or with minor dilution. Special compositions, particularly suitabe for ULV applications are solutions of finely divided suspensions in one or more carrier such as dialkylformamides, N-alkyl pyrrolidones, dimethyl sulfoxide, water, esters, ketones, glycols, glycol ethers and the like. Other suitable carriers include aromatic hydrocarbons (halogenated and nonhalogenated), aliphatic hydrocarbons (halogenated and nonhalogenated) and the like.

The following Examples are presented to further illustrate the formulation and application of the compounds of this invention. Parts and percentages in the following examples are by weight unless otherwise indicated.

Example 45 A water soluble powder of the following formula is prepared:

Dimethyl carbamoylphosphonate 95.0%

Sodium dioctyl sulfosuccinate 0.5%

Synthetic fine silica 4.5%

Example 46 A water extendable liquid of the following formula is prepared.

Diethyl carbamoylphosphonate Dimethyl formamide The diethyl carbamoylphosphate is dissolved with stirring in the dimethylformamide.

Eight kilograms of the formulation of Example 46 are added to 400 liters of water containing 0.5% Tween 20 (polyoxyethylenesorbitan monolaurate). This solution is sprayed to runoff on a freshly trimmed privet (Ligustrum ovalzfolium) in May. The treatment greatly reduces the growth of the hedge. Little labor is required to keep it attractive all season.

Example 47 A dust of the following formula is prepared:

Diisopropyl carbamoylphosphate 10.0%

Attapulgite clay l0.0%

Calcium carbonate coated with calcium stearate 80.0%

The dust is prepared by preblending the diisopropyl carbamoylphosphonate and attapulgite clay followed by hammer-milling the premix until essentially all of the particles are less than 50 microns in size. The ground premix is then thoroughly blended with the coated calcium carbonate to form the finished product.

It will be understood that the other compounds of this invention can also be formulated in a like manner.

The dust formulation of Example 47 is applied, using a helicopter, at a rate of kilograms per hectare to an area under an electric power line in which the brush and trees have been freshly trimmed in spring at the time when the leaves on most of the plants are just fully expanded. The application is made in the early morning when the foliage is wet with dew or just after a rain. This treatment retards the growth of a large number of species along the right-of-way including the following species: red maple (Acer rubrum), balck willow (Salix nigra), hawthorn (Crataegus spp.), sweet gum (Liquidamber styraciflua) and yellow poplar (Liriodendron tulipzfera Example 48 A wettable powder of the following formula is prepared.

Diallyl carbamoylphosphonate 75.0%

Sodium alkylnaphthalenesulfonate 2.5%

Partially disulfonated sodium 2.0% lignin sulfonate Kaolin clay 20.5%

The formulation is prepared by blending the ingredients in a ribbon blendor until the mixture is uniform. The mixture is then ground in a hammer-mill until essentially all of the particles are less than 50 microns in average diameter.

Five kilograms of the formulation of Example 48 are suspended in 400 liters of water and then sprayed to runoff on freshly trimmed trees and brush along the edge of a power line right-of-way. This treatment greatly reduces the growth of the trees and shrubs without permanent injury to them and they are prevented from growing over into the power line. The vegetation on the right-of-way is controlled by applying herbicides. This treatment reduces the labor required to maintain the line.

Example 49 A formulation which may be emulsified into water or extended with oil and having the following formula is prepared.

DitZ-methallyl) carbamoylphosphate 25.0%

Alkylaryl polyether alcohol 5.0%

Xylene 70.0%

The formulation is prepared by combining all of the ingredients and stirring to form a solution. Heat may be applied to increase the solution rate, if desired.

Eight kilograms of the formulation of Example 49 are suspended in 500 liters of water and sprayed to runoff on red maples growing under a power transmission line immediately after the trees are trimmed in early May. The treatment effectively retards the growth of the trees and the break and subsequent growth of adventitious buds. The treatment greatly increases the time until the next trimming is required to keep the trees from growing into the power lines with resultant savings in expenditure for powerline maintenance.

We claim:

1. A method for retarding the growth rate of plants while causing little or no apparent damage to the plants which comprises applying to said plant a growth retardant effective amount of a compound of the formula R2 RO-P- o-N I Re 0 1 where R is selected from the group consisting of alkyl of one through eight carbon atoms, chloroalkyl of two through eight carbon atoms containing up to three chlorine atoms, bromoalkyl of two through eight carbon atoms containing up to three bromine atoms, alkoxyalkyl of three through ten carbon atoms, total, alkenyl of two through eight carbon atoms, alkynyl of three through four carbon atoms, phenyl or benzyl;

R is selected from the group consisting of alkyl of one through eight carbon atoms, chloroalkyl of two through eight carbon atoms containing up to three chlorine atoms, bromoalkyl of two through eight carbon atoms containing up to three bromine atoms, alkoxyalkyl of three through ten carbon atoms, total, alkenyl of two through eight carbon atoms, alkynyl of three through four carbon atoms, phenyl or benzyl;

R is selected from the group consisting of hydrogen,

alkyl of one through four carbon atoms, hydroxyalkyl of two through four carbon atoms, alkenyl of three through four carbon atoms or alkylnyl of three through four carbon atoms;

R is selected from the group consisting of hydrogen,

alkyl of one through four carbon atoms, hydroxyalkyl of two through four carbon atoms, alkenyl of three through four carbon atoms or alkynyl of three through four carbon atoms;

R; and R can be taken together to form a bridge con sisting of (CH O(CH or (CH where n is 4, 5 or 6; and one of R or R can be where R, is hydrogen or alkyl of one through four carbon atoms and R is hydrogen or alkyl of one through four carbon atoms. 2. The method of claim ll wherein R isthe same as R and said R and R are as defined in claim 1.

3. The method of claim 1 wherein the compound ap' plied to said plant is a compound of the formula 2 R-O-P-C-N where R is selected from the group consisting of alkyl of one through four carbon atoms or alkenyl of two through four carbon atoms;

R is selected from the group consisting of alkyl of one through four carbon atoms or alkenyl of two through four carbon atoms; and

R and R are each hydrogen.

4. The method of claim 1 wherein the compound applied to said plant is diethyl carbamoylphosphate.

5. The method of claim 1 wherein the compound ap' plied to said plant is diallyl carbamoylphosphate.

6. The method of claim 1 wherein said plant is a woody plant.

7. The method of claim 2 wherein said plant is a woody plant.

8. The method of claim 3 wherein said plant is a woody plant.

9. The method of claim 4 wherein said plant is a woody plant.

10. The method of claim 5 wherein said plant is a woody plant. 

1. A METHOD FOR RETARDING THE GROWTH RATE OF PLANTS WHILE CAUSING LITTLE OR NO APPARENT DAMAGE TO THE PLANTS WHICH COMPRISES APPLYING TO SAID PLANT A GROWTH RETARDANT EFFECTIVE AMOUNT OF A COMPOUND OF THE FORMULA R-O-P(=O)(-O-R1)-CO-N(-R2)-R3 WHERE R IS SELECTED FROM THE GROUP CONSISTING OF ALKYL OF ONE THROUGH EIGHT CARBON ATOMS, CHLOROALKYL OF TWO THROUGH EIGHT CARBON ATOMS CONTAINING UP TO THREE CHLORINE ATOMS, BROMOALKYL OF TWO THROUGH EIGHT CARBON ATOMS CONTAINING UP TO THREE BROMINE ATOMS, ALKOXY OF THREE THROUGH TEN CARBON ATOMS, TOTAL, ALKENYL OF TWO THROUGH EIGHT CARBON ATOMS, ALKYNYL OF THREE THROUGH FOUR CARBON ATOMS PHENYL OR BENZYL: R1 IS SELECTED FROM THE GROUP CONSISTING OF ALKYL OF ONE THROUGH EIGHT CARBON ATOMS, CHLOROALKYL OF TWO THROUGH EIGHT CARBON ATOMS CONTAINING UP TO THREE CHLORINE ATOMS, BROMOALKYL OF TWO THROUGH EIGHT CARBON ATOMS CONTAINING UP TO THREE BROMINE ATOMS, ALKOXYALKYL OF THREE THROUGH TEN CARBON ATOMS, TOTAL, ALKENYL OF TWO THROUGH EIGHT CARBON ATOMS, ALKYNYL OF THREE THROUGH FOUR CARBON ATOMS, PHENYL OR BENZYL; R2 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, ALKYL OF ONE THROUGH FOURE CARBON ATOMS, HYDROXYALKYL OF TWO THROUGH FOUR CARBON ATOMS, ALKENYL OF THREE THROUGH FOUR CARBON ATOMS OR ALKYLNYL OF THREE THROUGH FOUR CARBON ATOMS; R3 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, ALKYL OF ONE THROUGH FOUR CARBON ATOMS, HYDROXYALKYL OF TWO THROUGH FOUR CARBON ATOMS, ALKENYL OF THREE THROUGH FOUR CARBON ATOMS OR ALKYNYL OF THREE THROUGH FOUR CARBON ATOMS; R2 AND R3 CAN BE TAKEN TOGETHER TO FORM A BRIDGE CONSISTING OF -(CH2)2-O-(CH2)2-OR-(CH2)N-WHERE N IS 4, 5 OR 6; AND ONE OF R2 OR R3 CAN BE -N(-R4)-R5 WHERE R4 IS HYDROGEN OR ALKYL OF ONE THROUGH FOUR CARBON ATOMS AND R5 IS HYDROGEN OR ALKYL OF ONE THROUGH FOUR CARBON ATOMS.
 2. The method of claim 1 wherein R is the same as R1 and said R and R1 are as defined in claim
 1. 3. The method of claim 1 wherein the compound applied to said plant is a compound of the formula
 4. The method of claim 1 wherein the compound applied to said plant is diethyl carbamoylphosphate.
 5. The method of claim 1 wherein the compound applied to said plant is diallyl carbamoylphosphate.
 6. The method of claim 1 wherein said plant is a woody plant.
 7. The method of claim 2 wherein said plant is a woody plant.
 8. The method of claim 3 wherein said plant is a woody plant.
 9. The method of claim 4 wherein said plant is a woody plant.
 10. The method of claim 5 wherein said plant is a woody plant. 